Obstructive sleep apnea (OSA) is a modifiable cause of hypertension but is often underdiagnosed.¹ Patients with hypertension are at a higher risk for cardiac and cerebrovascular diseases and are thus recommended to undergo screening and treatment of OSA.¹ While the continuous positive airway pressure (CPAP) machine is the first-line treatment for OSA that helps maintain airway patency during sleep, many patients either refuse to use it or struggle to adhere to the treatment.¹ A mandibular advancement device (MAD) is an alternative treatment method that reduces airway collapsibility by advancing the mandible during sleep.¹ MAD has been shown to improve sleepiness and quality of life, with better acceptance and tolerance.¹ However, whether treating OSA using MAD is as effective as CPAP in reducing blood pressure (BP) is unclear due to limitations of early studies.¹ During the ACC Annual Scientific Session 2024, Professor Lee, Chi-Hang Ronald from the National University Heart Centre, Singapore, presented the results from the CRESCENT trial which aimed to compare the effectiveness of MAD against CPAP in reducing BP in patients with moderate-to-severe OSA, hypertension and high cardiovascular (CV) risk.¹

This trial recruited Chinese patients ≥40 years of age with essential hypertension on ≥1 medication for BP control who are at high CV risk, defined as having at least 1 of the following: diabetes mellitus, stroke, significant coronary artery disease (CAD), chronic kidney disease, or ≥75 years of age.¹ Patients were excluded if they had known OSA on treatment, secondary hypertension, contraindications to MAD, or had experienced a hypertensive crisis, acute coronary syndrome (ACS), or acute heart failure (HF) in the past 30 days.¹ In total, 306 patients completed polysomnography, of which 220 patients were diagnosed with OSA and were randomized 1:1 to receive MAD (n=110) or CPAP (n=110).¹ At baseline, ambulatory blood pressure monitoring (ABPM), cardiovascular magnetic resonance (CMR), ambulatory electrocardiogram (ECG), as well as an assessment of cardiac biomarkers and quality of life (QoL) were performed.¹ ABPM, CRN, biomarkers, QoL and ambulatory ECG were assessed after 6 months of treatment and continued to be followed up until 12 months.¹ The overall withdrawal rate was 9.5% (MAD: n=12, CPAP: n=9) which was lower than the 20% anticipated.¹

Using 3 different criteria for good treatment adherence as defined by the American Academy of Sleep Medicine (AASM), the MAD group showed higher device adherence over 6 months compared to the CPAP group (≥4h per night in ≥70% of the night: 69.4% vs. 64.3%; average usage ≥4hr per night: 75.3% vs. 68.7%; average usage ≥6h per night: 56.5% vs. 23.2%).¹ Both MAD and CPAP significantly improved sleepiness at 6 months compared to baseline with a 15.4% (p=0.001) and 27.5% (p<0.001) reduction in sleepiness in the MAD group and the CPAP group, respectively.¹

In this cohort of OSA participants with relatively well-controlled BP at baseline, MAD led to a greater change in mean arterial BP at 6 months compared to CPAP (24h mean blood pressure [MBP]: -2.5mmHg vs. 0.0mmHg; awake MBP: -1.5mmHg vs. -1.0mmHg; asleep MBP: -2.0mmHg vs. 1.0mmHg).¹ This translates to a between-group difference in 24h MBP of -1.64mmHg (95% CI: -3.51 to 0.24), favoring the MAD device with a confidence interval that does not exceed the predefined non-inferiority margin of 1.5mmHg.¹ The results remain unchanged even after excluding 21 participants who had changes in BP medication during the 6-month treatment period.¹ The BP-reducing efficacy of MAD was also shown to be consistent regardless of the time of day, with a more pronounced between-group difference associated with nighttime BP compared to daytime BP (systolic BP: -2.85mmHg vs. -1.83mmHg; diastolic BP: -2.26mmHg vs. -0.83mmHg).¹

In summary, the CRESCENT trial showed that both MAD and CPAP were effective in improving daytime sleepiness and MAD was non-inferior to CPAP for reducing 24h mean arterial BP at 6-month follow-up.¹ Moreover, the between-group difference in BP reduction favored MAD and was most pronounced for nighttime BP.¹